Driving apparatus, exposure apparatus, and device manufacturing method

ABSTRACT

This invention provides a technique that can cancel a reaction force accompanying drive of an object while moderating a limit for a driving pattern to drive the object in X and Y directions. A driving apparatus includes a first actuator which drives the object in X and Y directions, a second actuator which drives a reaction force counter which receives a reaction force generated when the first actuator drives the object, and a controller which controls the second actuator on the basis of X- and Y-direction positions of the object to cancel, by the second actuator, the reaction force to be received by the reaction force counter when the object is driven by the first actuator.

FIELD OF THE INVENTION

The present invention relates to a driving apparatus, exposureapparatus, and device manufacturing method and, more particularly, to adriving apparatus for moving an object such as a substrate, chuck, andstage (top plate), an exposure apparatus having the driving apparatus,and a device manufacturing method using the exposure apparatus.

BACKGROUND OF THE INVENTION

A typical example of an exposure apparatus used to manufacture a devicesuch as a semiconductor device includes a step & repeat type exposureapparatus (stepper) which sequentially exposes the pattern of a master(reticle or mask) onto a plurality of exposure regions on a substrate,(e.g., a wafer or glass substrate) through a projection optical systemwhile stepping the substrate, and a step & scan type exposure apparatus(scanner) which repeats stepping and scanning exposure to repeatexposure and transfer on the plurality of regions on a substrate. Inparticular, the step & scan type exposure apparatus uses exposure lightafter limiting it with a slit to a component comparatively close to theoptical axis of a projection optical system, so that it can expose amicropattern at higher accuracy with a wider angle of view. Someexposure apparatus draws a pattern on a substrate with anelectrosensitive particle beam such as an electron beam or ion beam inplace of light.

Each of the exposure apparatuses has a stage device or driving apparatus(wafer stage or reticle stage) which aligns a wafer or reticle by movingit at high speed. In such an exposure apparatus, when the stage isdriven, a reaction force of an inertia force accompanying accelerationand deceleration is generated. When the reaction force is transmitted toa stage surface plate on which the stage is mounted, the stage surfacemay swing or vibrate. Such vibration induces characteristic vibration ofthe mechanism system of the exposure apparatus to generatehigh-frequency vibration which may interfere with faster,higher-accuracy alignment.

To solve the problems relating to the reaction force, several proposalshave been made. For example, according to the apparatus described inJapanese Patent Laid-Open No. 5-77126, the stator of a linear motorwhich drives a stage is supported on the floor independently of a stagesurface plate, so that swing of the stage surface plate caused by thereaction force is prevented. According to the apparatus described inJapanese Patent Laid-Open No. 5-12.1294, a machine frame supports awafer stage and projection lens. An actuator which generates a force inthe horizontal direction applies to the machine frame a compensatingforce equivalent to a reaction force accompanying the drive of thestage. Swing of the apparatus caused by the reaction force is thusdecreased.

In any of the conventional examples described above, although the swingof the stage apparatus itself can be decreased, the reaction forceaccompanying the drive of the stage is transmitted to the floor directlyor through a member that can be substantially regarded as integral withthe floor. This may oscillate the floor and vibrate devices set aroundthe exposure apparatus, thus adversely affecting the peripheral devices.Usually, the floor where the exposure apparatus is installed has anatural frequency of about 20 Hz to 40 Hz. As the exposure apparatus isoperated, when the characteristic vibration of the floor is induced, itadversely largely affects the peripheral devices.

Recently, as the processing speed (throughput) increases, the stageacceleration increases more and more. For example, in a step & scan typeexposure apparatus, the maximal acceleration of the stage reaches ashigh as 4 G in the reticle stage and 1 G in the wafer stage. As thereticle or substrate increases in size, the stage mass also increases.Therefore, the driving force defined by <mass of a movingobject>×<acceleration> becomes very large, and its reaction force isenormous. As the reaction force increases in this manner, oscillation ofthe floor for installation caused by the reaction force has become anon-negligible issue.

The size of the apparatus also increases largely, and in a manufacturingfactory where many manufacturing apparatuses are installed, an increasein area occupied by the apparatuses is becoming an apparent issue. Morespecifically, when the vibration transmitted from one apparatus to thefloor is large, to prevent the other apparatuses from being influencedby the vibration, the distances among the apparatuses must be increased,and finally the area actually occupied by the respective apparatusesincreases.

Japanese Patent Laid-Open No. 2003-318082 discloses, in a drivingapparatus which drives an object by a linear motor, use of the stator ofthe linear motor as a reaction force counter. According to the drivingapparatus described in this reference, when an object which stays stillat the first position is to be moved to the second position and be setstill, the linear motor is controlled so that the object moves along astraight line connecting the first and second positions, to cancel amoment reaction force accompanying acceleration and deceleration of theobject.

According to the technique described in Japanese Patent Laid-Open No.2003-318082, the wafer stage must be moved along a straight line. In thestep & scan type exposure apparatus, assume that the entire moving pathof a wafer stage to sequentially expose a plurality of exposure regionsS is formed of straight lines, as shown in FIG. 5. The wafer stage mustbe stopped at the terminal point of each straight line. This caninterfere with an increase in throughput. In view of this, tosequentially expose the plurality of exposure regions S whilecontinuously driving the wafer stage along a smooth curved line, asexemplified in FIG. 6, is sought for.

To continuously move the wafer stage along the smooth curved lines,moderation of the limit for a Y-direction (X-direction) driving patternby an X-direction (Y-direction) driving pattern (driving profile) issought for.

SUMMARY OF THE INVENTION

The present invention has been made on the basis of the recognition ofthe above problems, and has as its object to provide a technique thatcan cancel a reaction force accompanying drive of an object whilemoderating a limit for a driving pattern to drive the object in X and Ydirections.

According to one aspect of the present invention, there is provided adriving apparatus for moving an object, comprising a first actuatorwhich drives the object in X and Y directions, a second actuator whichdrives a reaction force counter which receives a reaction forcegenerated when the first actuator drives the object, and a controllerwhich controls the second actuator on the basis of X- and Y-directionpositions of the object so as to cancel, by the second actuator, thereaction force to be received by the reaction force counter when theobject is driven by the first actuator.

According to a preferred embodiment of the present invention, forexample, the controller calculates X- and Y-direction accelerations ofthe object on the basis of the X- and Y-direction positions of theobject, and controls the second actuator on the basis of the X- andY-direction positions of the object and the X- and Y-directionaccelerations of the object. Alternatively, the driving apparatus canfurther comprise an acceleration sensor which detects X- and Y-directionaccelerations of the object. The controller can control the secondactuator on the basis of the X- and Y-direction accelerations of theobject from the acceleration sensor and the X- and Y-direction positionsof the object.

According to a preferred embodiment of the present invention, forexample, the controller controls the second actuator so as to cancel, bythe second actuator, X- and Y-direction reaction forces and a momentreaction force which are to be received by the reaction force counterwhen the object is driven by the first actuator.

According to a preferred embodiment of the present invention, forexample, the controller calculates X- and Y-direction reaction forcesand a moment reaction force which are to be received by the reactionforce counter when the object is driven by the first actuator, andgenerates a profile to drive the reaction force counter on the basis ofthe X- and Y-direction reaction forces and the moment reaction force.

According to a preferred embodiment of the present invention, forexample, the controller calculates the X- and Y-direction reactionforces Fx and Fy to be received by the reaction force counter and themoment reaction force Fr in accordance with:Fx=m·AccXFy=m·AccY, andFr=y·Fx−x·Fy=m(y·AccX−x·AccY)where m, x, and y are a weight, X-direction position, and Y-directionposition, respectively, of the object, and AccX and AccY are X- andY-direction accelerations, respectively. The controller generates aprofile to drive the reaction force counter such that Σ(FMx)=−Fx,Σ(FMy)=−Fy, and Σ(FMr)=−Fr are established where Σ(FMx) and Σ(FMy) aresums of X- and Y-direction thrusts, respectively, of the secondactuator, and Σ(FMr) is a sum of moment thrusts. For example, theprofile can comprise a profile that provides a thrust command value.

According to a preferred embodiment of the present invention, forexample, the controller generates a profile to drive the second actuatorsuch that Σ(M(i)·AccMX(i))=−Fx, Σ(M(i)·AccMY(i))=−Fy, andΣ(J(i)·AccMJ(i))=−Fr are established where (M(i) is a weight of each ofa plurality of reaction counters which receive the reaction forcegenerated when the first actuator drives the object, AccMX(i) andAccMY(i) are respectively X- and Y-direction accelerations of each ofthe plurality of reaction force counters, and J(i) and AccMJ(i) arerespectively a moment of inertia and angular velocity of each of theplurality of reaction force counters. For example, the profile cancomprise a profile that provides an acceleration command value. Forexample, the controller can convert the acceleration command value intoa speed command value and control the second actuator with the speedcommand value, or convert the acceleration command value into a positioncommand value and control the second actuator with the position commandvalue.

According to a preferred embodiment of the present invention, thereaction force counter can include a stator of the first actuator.

According to a preferred embodiment of the present invention, forexample, the controller controls the second actuator to graduallydecelerate the reaction force counter when a speed of the reaction forcecounter is not zero while a speed of the object is zero.

According to the second aspect of the present invention, there isprovided an exposure apparatus which has a chuck and transfers or drawsa pattern onto a substrate chucked on the chuck, and in which the chuckcan be driven by the driving apparatus described above.

According to the third aspect of the present invention, there isprovided a device manufacturing method of manufacturing a device byusing an exposure apparatus described above.

According to the present invention, for example, a reaction forceaccompanying drive of an object can be canceled while moderating thelimit for a driving pattern to drive the object in an X and Ydirections.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a block diagram showing an arrangement of a controller whichcontrols a driving apparatus;

FIG. 2 includes graphs showing an example of a driving pattern whichperforms acceleration/deceleration in X and Y directions independentlyof each other;

FIG. 3 includes graphs showing an example of an acceleration profilegenerated by a reaction force counter profile generator;

FIGS. 4A and 4B are views showing the schematic arrangement of a drivingapparatus (wafer stage) built into an exposure apparatus according to apreferred embodiment of the present invention;

FIG. 5 is a view showing a stage driving example that can cancel areaction force completely with an apparatus described in Japanese PatentLaid-Open No. 2003-318082;

FIG. 6 is a view showing a stage driving example that can improve thethroughput;

FIG. 7 is a view for explaining a moment reaction force;

FIG. 8 includes graphs showing examples of the movements of an X-Yslider and reaction force counter; and

FIG. 9 is a view showing a schematic arrangement of an exposureapparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The preferred embodiments of the present invention will be describedwith reference to the accompanying drawings.

First Embodiment

FIGS. 4A and 4B show the schematic arrangement of a driving apparatus(wafer stage) built into an exposure apparatus according to a preferredembodiment of the present invention, in which FIG. 4A is a plan view,and FIG. 4B is a sectional view.

Referring to FIGS. 4A and 4B, a top plate 30 is provided with a waferchuck 31 and bar mirrors 50 and 51 for position measurement. The waferchuck 31 chucks and holds a wafer (substrate) as a positioning target bya chucking method such as vacuum suction or electrostatic attraction.The bar mirrors 50 and 51 reflect measurement light from laserinterferometers (not shown). The top plate 30 is levitated in anon-contact manner with respect to an X-Y slider 38 by a self weightcompensator (not shown) utilizing a magnet, and can move in 6-axisdirections. The top plate 30 is finely driven in the 6-axis directions(X, Y, and Z directions and directions about X-, Y-, and Z-axes) byactuators which generate driving forces between the top plate 30 and X-Yslider 38. As the actuators for 6-axis fine driving, two X-directionlinear motors, one Y-direction linear motor, and three Z-directionlinear motors are provided. When the two X-direction fine-moving linearmotors are driven in opposite directions, the top plate 30 can be drivenabout the Z-axis (θ direction). When the driving forces of the threeZ-direction fine-moving linear motors are adjusted, the top plate 30 canbe driven about the X-axis (ωX direction) and Y-axis (ωY direction).Coils serving as the stators of the fine-moving linear motors areprovided to the X-Y slider 38, and permanent magnets serving as themovable elements of the fine-moving linear motors are provided to thetop plate 30.

The X-Y slider 38 is guided in the X and Y directions by an X-guide bar28 and Y-guide bar 29 through air bearings (hydrostatic bearings) 35 a.The X-Y slider 38 is guided in the Z direction by the upper surface of areference structure 4 through air bearings (hydrostatic bearings) 35 b.

Movable elements (magnets) 26 and 126, and 27 and 127 of the linearmotors (first actuators) are attached near the two ends of the X-guidebar 28 and near the two ends of the Y-guide bar 29, respectively. Underthe control of a controller 100, when a current is supplied to two Xlinear motors (coils) 24 and 124 and two Y linear motors (coils) 25 and125, the Lorentz force is generated, and the X-guide bar 28 and Y-guidebar 29 can be driven in the Y and X directions, respectively. The two Xlinear motors (coils) 24 and 124 and the two Y linear motors (coils) 25and 125 are guided in the Z direction by the upper surface of thereference structure 4 through air bearings (hydrostatic bearings) 34,and can freely move in the X and Y directions (planar direction). In thefollowing description, the linear motor stators 24, 124, 25, and 125 arealso respectively referred to as YR, YL, XB, and XF.

Under the control of the controller 100, the linear motor stators 24 and124 are driven in the Y direction by linear motor stator control linearmotors (second actuators) 32 and 132. Similarly, the linear motorstators 25 and 125 are driven in the X direction by linear motor statorcontrol linear motors (second actuators) 33 and 133.

In the driving apparatus shown in FIGS. 4A and 4B, the reaction forcecounter formed of the stators of the linear motors is divided into fourcounters XB (25), XF (125), YR (24), and YL (124).

A driving reaction force generated when the X-Y slider 38 is driven inthe X direction can be canceled by the reaction force counters XB (25)and XF (125). More specifically, assuming that the X-direction componentof a driving force F (t) of the X-Y slider 38 is expressed as F_(x)(t),F_(x)(t) is a driving force that drives the movable elements 27 and 127of the X linear motors, and its reaction force is −F_(x)(t). TheX-direction reaction force −F_(x)(t) is received by the reaction forcecounter XB (25) and XF (125) formed of the stators of the X-directionlinear motors. The X-direction reaction force can be canceled ifequation (1) is established:F _(X)(t)=−(F _(XF)(t)+F _(XB)(t))  (1)where F_(XF)(t) is a force acting on the reaction force counter XF (125)and F_(XB)(t) is a force acting on the reaction force counter XB (25).

Similarly, a Y-direction driving reaction force can be canceled by thereaction force counters YL (124) and YR (24). More specifically,assuming that the Y-direction component of the driving force F(t) of theX-Y slider 38 is expressed as F_(y)(t), F_(y)(t) is a driving force thatdrives the movable elements 26 and 126 of the Y linear motors, and itsreaction force is −F_(y)(t). The Y-direction reaction force −F_(y)(t) isreceived by the reaction force counter YL (126) and YR (26) formed ofthe stators of the Y linear motors. The Y-direction reaction force canbe canceled if equation (2) is established:F _(Y)(t)=−(F _(YL)(t)+F _(YR)(t))  (2)where F_(YL)(t) is a force acting on the reaction force counter YL andF_(YR)(t) is a force acting on the reaction force counter YR.

A moment-direction reaction force (reaction force of rotation) will beconsidered. FIG. 7 shows a reaction force in the direction of moment inthe driving apparatus shown in FIGS. 4A and 4B. A moment reaction forceγ_(x)(t) acting on the X-guide bar 28 from the X-Y slider 38 can beexpressed by the following equation (3):γ_(x)(t)=y(t)·m·AccX(t)  (3)where x(t) and y(t) are the X- and Y-direction positions of the X-Yslider 38 with respect to the barycenter of the entire driving apparatusas the center, m is the weight of the X-Y slider 38, and AccX(t) andAccY(t) are respectively the X- and Y-direction accelerations of the X-Yslider 38.

A moment reaction force γ_(y)(t) acting on the Y-guide bar 29 from theX-Y slider 38 can be expressed by the following equation (4):γ_(y)(t)=−x(t)·m·AccY(t)  (4)

A moment reaction force γ(t) is the sum of the moment γ_(x)(t) acting onthe X-guide bar 28 and the moment γ_(y)(t) acting on the Y-guide bar 29,and is accordingly expressed by the following equation (5):γ(t)=m(y(t)·AccX(t)−x(t)·AccY(t))  (5)

Assuming that the lengths of the X- and Y-guide gars 28 and 29 arerespectively 2Lx and 2Ly, as is apparent from FIG. 7, the momentreaction forces γ(t) and γ_(y)(t) respectively acting on the guide bars28 and 29 from the counter masses XF and XB, and YL and YR can beexpressed by the following equations (6):γ_(x)(t)=−(F _(YL)(t)−F _(YR)(t))L _(x)γ_(y)(t)=−(F _(XB)(t)−F _(XF)(t))L _(y)  (6)

Similarly, as the moment reaction force γ(t) is the sum of the momentγ_(x)(t) acting on the X-guide bar 28 and the moment γ_(y)(t) acting onthe Y-guide bar 29, if the following equation (7): $\begin{matrix}\begin{matrix}{{\gamma(t)} = {{\gamma_{x}(t)} + {\gamma_{y}(t)}}} \\{= {{{- \left( {{F_{YL}(t)} - {F_{YR}(t)}} \right)}L_{x}} - {\left( {{F_{XB}(t)} - {F_{XP}(t)}} \right)L_{y}}}}\end{matrix} & (7)\end{matrix}$is established, then the moment reaction force can be canceled.

In this driving apparatus, under the control of the controller 100, theX-Y slider 38 is driven, and simultaneously the reaction force countersXF (125), XB (25), YL (124), and YR (24) formed of the linear motorstators are driven by the linear motor stator control linear motors 133,33, 132, and 32 by forces expressed by the following equations (8):F _(XF)(t)=−(F _(x)(t)−γ(t)α)/2F _(XB)(t)=−(F _(x)(t)−γ(t)α)/2F _(YL)(t)=−(F _(y)(t)−γ(t)α)/2F _(YR)(t)=−(F _(y)(t)−γ(t)α)/2

When the reaction force counters XF (125), XB (25), YL (124), and YR(24) are driven by the forces expressed by equations (8), equation (1)is established for the forces acting in the X direction on the reactionforce counters XF (125) and XB (25), as shown in the following equation(9):−(F _(XF)(t)+F _(XB)(t))=F _(X)(t)  (9)Accordingly, the reaction force in the X direction can be canceledcompletely.

Similarly, equation (2) is established in the Y direction, as shown inthe following equation (10):−(F _(YL)(t)+F_(YR)(t))=F _(Y)(t)  (10)Accordingly, the reaction force in the Y direction can be canceledcompletely.

Furthermore, the moment reaction force is as shown in the followingequation (11): $\begin{matrix}{{{{- \left( {{F_{YL}(t)} - {F_{YR}(t)}} \right)}L_{x}} - {\left( {{F_{XB}(t)} - {F_{XF}(t)}} \right)L_{y}}} = {\left( {{\beta\quad L_{x}} + {\alpha\quad L_{y}}} \right){\gamma(t)}}} & (11)\end{matrix}$

Accordingly, if α and β that establish the following equation (12):βL _(x) +αL _(y)=1  (12)are selected, then equation (7) is established and the moment reactionforce can be canceled completely.

For example, if α and β are determined in accordance with the followingequations (13):α=1/(2L _(y))β=1/(2L _(x))  (13)then the moment reaction force can be distributed into the four reactionforce counters XF, XB, YL, and YR.

The driving profiles with which the linear motor stator control linearmotors 133, 33, 132, and 32 respectively drive the reaction forcecounters XF (125), XB (25), YL (124), and YR (24) can be calculated realtime by the controller 100 when necessary on the basis of theaccelerations and positions in the X and Y directions of the X-Y slider38.

Equations (8) can be written into the following equations (14):AccXF=−(m·AccX−γα)/(2MXF)AccXB=−(m·AccX−γα)/(2MXB)AccYL=−(m·AccY−γβ)/(2MYL)AccYR=−(m·AccY−γβ)/(2MYR)γ=m(y·AccX−x·Accy)  (14)where MXF and AccXF are the weight and acceleration, respectively, ofthe reaction force counter XF, MXB and AccXB are the weight andacceleration, respectively, of the reaction force counter XB, MYL andAccYL are the weight and acceleration, respectively, of the reactionforce counter YL, and MYR and AccYR are the weight and acceleration,respectively, of the reaction force counter YR.

In this manner, acceleration command values that can be supplied to thelinear motor stator control linear motors 133, 33, 132, and 32 toaccelerate the reaction force counters XF, XB, YL, and YR, respectively,can be determined on the basis of the accelerations AccX and AccY andpositions x and y of the X-Y slider 38.

FIG. 1 is a block diagram showing an arrangement of the controller 100.Referring to FIG. 1, an X-position command unit 201 generates a commandvalue REF-X which instructs the X-direction target position of the X-Yslider 38 in accordance with the X-direction position profile. AY-position command unit 202 generates a command value REF-Y whichinstructs the Y-direction target position of the X-Y slider 38 inaccordance with the Y-direction position profile. The controller 100shown in FIG. 1 forms a position feedback servo system that moves theX-Y slider 38 in accordance with the X- and Y-direction position commandvalues REF-X and REF-Y generated by the X- and Y-position command units201 and 202, respectively.

The X- and Y-direction positions of the X-Y slider 38 are controlled bydriving the Y- and X-guide bars 29 and 28 in the X and Y directions,respectively. The Y-guide bar 29 is driven by the linear motors XB (25)and XF (125). The X-guide bar 28 is driven by the linear motors YL (124)and YR (24).

An X-position measurement unit 250 measures the X-direction position ofthe X-Y slider 38, and a Y-position measurement unit 251 measures theY-direction position of the X-Y slider 38. The X- and Y-positionmeasurement units 250 and 251 can respectively include laserinterferometers which measure the positions of the X and Y bar mirrors50 and 51, respectively, shown in FIGS. 4A and 4B.

A subtracter 205 subtracts the X-direction measurement position providedby the X-position measurement unit 250 from the X-direction targetposition command value REF-X provided by the X-position command unit201, and outputs an X-direction position deviation (control deviation).The position deviation is converted into an X-axis thrust command valueFx by an X-axis compensator (Gx) 207. The compensator (Gx) 207 caninclude a PID compensator, low-pass filter, notch filter, and the like.

A subtracter 206 subtracts the Y-direction measurement position providedby the Y-position measurement unit 251 from the Y-direction targetposition command value REF-Y provided by the Y-position command unit202, and outputs a Y-direction position deviation (control deviation).The position deviation is converted into a Y-axis thrust command valueFy by a Y-axis compensator (Gy) 208. The compensator (Gy) 208 caninclude a PID compensator, low-pass filter, notch filter, and the like.

A thrust distributor 210 distributes the thrust to the linear motorstators (reaction force counters) XF (125), XB (25), YL (124), and YR(24) on the basis of the X- and Y-direction thrust command values Fx andFy and the X- and Y-direction position command values REF-X and REF-Yrespectively provided by the position command units 201 and 202. ThrustsFxb, Fxf, Fyl, and Fyr calculated by the thrust distributor 210 areoutput to the linear motor stators XB (25), XF (125), YL (124), and YR(24) through drivers (not shown). Thus, the X- and Y-guide bars 28 and29 are driven to move the X-Y slider 38.

As described above, the X-Y slider 38 can be controlled by the positionfeedback servo system, and driven in the X and Y directions inaccordance with position profiles independent of each other.

The lower half of FIG. 1 shows the control system of the reaction forcecounters XF (125), XB (25), YL (124), and YR (24) which serve also asthe linear motor stators. The reaction force counters can also becontrolled by the position feedback servo system. A description will bemade on the reaction force counter XB (25). A subtracter 259 calculatesthe position deviation between the position command value (positionprofile) of the reaction force counter XB (25) provided by asecond-order integrator 295 and the measurement position. A compensator255 converts the calculated position deviation into a thrust commandvalue for the linear motor stator control linear motor 33, and drivesthe reaction force counter (XB) 25. The reaction force counters (XF)125, YL (124), and RY (24) are also provided with similar positionfeedback servo systems, and are driven in accordance with positioncommand values (position profiles) provided by second-order integrators296 to 298.

Each position feedback servo system can include, e.g., a high-speedoperation signal processor such as a DSP (Digital Signal Processor), andbe controlled in real time in a softwafer manner at, e.g., apredetermined sampling rate.

A reaction force counter profile generator 270 generates accelerationcommand values to control the respective reaction force counters XB(25), XF (125), YR (24), and YL (124) in accordance with equations (14)on the basis of the accelerations AccX and AccY and positions x and Y ofthe X-Y slider 38. The reaction force counter profile generator 270receives the X- and Y-position command values REF-X (position x) andREF-Y (position y) and X and Y acceleration command values AccX and AccYof the X-Y slider 38 and outputs acceleration command values AccXB,AccXF, AccYL and AccYR to be supplied to the respective reaction forcecounters XB (25), XF (125), YR (24), and YL (124).

The acceleration command values AccX and AccY can be generated bysubjecting the X- and Y-position command values REF-X and REF-Y tosecond-order differentiation sequentially by second-orderdifferentiators 281 and 282. Alternatively, the acceleration commandvalues AccX and AccY can be obtained by detecting the X- and Y-directionaccelerations of the X-Y slider 38 by acceleration sensors. The reactionforce counter profile generator 270 can include, e.g., a high-speedoperation signal processor such as a DSP (Digital Signal Processor), andbe controlled in real time in a softwafer manner at, e.g., apredetermined sampling rate.

The acceleration command values AccXB, AccXF, AccYL, and AccYR generatedby the reaction force counter profile generator 270 are subjected tosecond-order integration by the second-order integrators 295 to 298 toform position command values, and are supplied to the position servoloops of the reaction force counters as position profiles. Therespective reaction force counters are driven by the position servoloops in accordance with the supplied position profiles, as describedabove.

With the above arrangement, even if the driving position profiles of theX-Y slider 38 are given in the X and Y directions independently of eachother, the position command values (position profiles) to the reactionforce counters are calculated sequentially in accordance with equations(14), so that the X- and Y-direction reaction forces and the momentreaction force can be canceled completely.

For example, as shown in FIG. 2, assume a case wherein the X-Y slider 38is to be continuously driven such that not only the acceleration(thrust) in the X-axis direction but also the acceleration (thrust) inthe Y-axis direction are to be changed. In this case, the reaction forcecounter profile generator 270 shown in FIG. 1 generates accelerationprofiles as shown in FIG. 3 in accordance with equations (14). Thelinear motor stator position control linear motors 133, 33, 132, and 32drive the reaction force counters XF (125), XB (25), YL (124), and YR(24) in accordance with the generated acceleration profiles, tocompletely cancel the X- and Y-direction reaction forces and the momentreaction force accompanying the drive of the X-Y slider 38.

While the moment reaction force can be canceled completely, depending onthe driving profiles of the X-Y slider 38, even if the X-Y slider 38stops and its speed becomes zero, the reaction force counters XF (125),XB (25), YL (124), and YR (24) do not become zero in speed, as shown inFIG. 8, but may move at predetermined speeds. In this case, thecontroller 100 desirably gradually decreases the speeds of the reactionforce counters to stop the reaction force counters.

The above technique can be generalized as follows. More specifically,the X-direction reaction force Fx=m·AccX, Y-direction reaction forceFy=m·AccY, a moment reaction force Fr=y·Fx−x·Fy=m(y·AccX−x·AccY) aresequentially calculated where m, x, and y are the weight, X-directionposition, and Y-direction position, respectively, of the X-Y stage, andAccX and AccY are the X- and Y-direction accelerations, respectively, ofthe X-Y stage. Also, the driving profiles of the reaction force countersare sequentially calculated to establish Σ(FMx)=−Fx, Σ(FMy)=−Fy, andΣ(FMr)=−Fr where Σ(FMx) is the sum of the thrusts that drive thereaction force counters in the X direction, Σ(FMy) is the sum of thethrusts that drive the reaction force counters in the Y direction, andΣ(FMr) is the sum of the moment thrusts that drive the reaction forcecounters. Thus, the respective reaction force counters are driven.Hence, all of the X- and Y-direction reaction forces and the momentreaction force can be canceled completely.

Alternatively, the above technique can also be read in the followingmanner. More specifically, the driving profiles of the reaction forcecounters are calculated sequentially to establish Σ(M(i)·AccMX(i))=−Fx,Σ(M(i)·AccMY(i))=−Fy, and Σ(J(i)·AccMJ(i))=−Fr where (M(i) is the weightof each of the plurality of reaction counters, AccMX(i) and AccMY(i) arerespectively the X- and Y-direction accelerations of each reaction forcecounter, and J(i) and AccMJ(i) are respectively the moment of inertiaand the angular velocity of each reaction force counter. Then, therespective reaction force counters are driven. Hence, all of the X- andY-direction reaction forces and the moment reaction force can becanceled completely.

Second Embodiment

The control system of the reaction force counter can include a speedservo loop. The acceleration command values AccXB, AccXF, AccYL, andAccYR of the reaction force counters of the first embodiment can beintegrated to generate a speed command value profile. The speed commandvalue profile can be used as a profile to control each reaction forcecounter.

Third Embodiment

The reaction force counter can be controlled by a feed-forward controlsystem. For example, thrust command values can be obtained from AccXB,AccXF, AccYL, and AccYR of the first embodiment, and supplied directly(that is, without calculating deviations) to the drivers of linearmotors 133, 33, 132, and 32 that drive the reaction force counters.

[Application]

FIG. 9 is a view showing a schematic arrangement of an exposureapparatus in which the driving apparatus shown in FIGS. 4A and 4B isincorporated as a wafer stage. In the exposure apparatus shown in FIG.9, a driving apparatus 200 holds a wafer (substrate) W on a wafer chuck31, and moves the wafer W under the control of a controller 100 inaccordance with a position profile.

A reticle (master) R held on a reticle stage 220 is illuminated by anillumination optical system 210, and the pattern of the reticle R isprojected onto the wafer W through a projection optical system 230, andexposed. The exposure apparatus can be, e.g., a step & repeat or step &scan type exposure apparatus.

According to this exposure apparatus, even when the stage (top plate) 30is driven in accordance with the curved line exemplified in, e.g., FIG.6, the X- and Y-direction reaction forces acting on the reaction forcecounter and the moment reaction force which accompany the drive can becanceled. More specifically, according to this exposure apparatus, evenwhen the stage (30) is driven in accordance with the driving profilesthat are independent of each other in the X and Y directions, the X- andY-direction reaction forces and the moment reaction force whichaccompany the drive can be canceled.

Therefore, even when the stage 30 is driven in accordance with thecurved line exemplified in, e.g., FIG. 6, vibration and swingaccompanying the drive can be decreased. Thus, the overlay accuracy,line width accuracy, and the like can be improved while the throughputis improved simultaneously. The influence of the reaction forcesaccompanying acceleration and deceleration of the stage can bedecreased, and the influence on other devices set on the same floor canbe decreased. Thus, the effective installation area can be reduced.

According to the exposure apparatus as described above, an excellentdevice can be manufactured. Such a manufacturing method repeats alithography process including, e.g., the step of applying aphotosensitive agent to a substrate such as a wafer or glass substrate,the step of transferring or drawing a pattern on the substrate by usingthe exposure apparatus described above, and the step of developing thepattern, to manufacture a device such as a semiconductor device, liquidcrystal device, and MEMS device.

As many apparently widely different embodiments of the present inventioncan be made without departing from the spirit and scope thereof, it isto be understood that the invention is not limited to the specificembodiments thereof except as defined in the appended claims.

CLAIM OF PRIORITY

This application claims priority from Japanese Patent Application No.2004-008404 filed on Jan. 15, 2004, the entire contents of which arehereby incorporated by reference herein.

1. A driving apparatus for moving an object, comprising: a firstactuator which drives the object in X and Y directions; a secondactuator which drives a reaction force counter which receives a reactionforce generated when said first actuator drives the object; and acontroller which controls said second actuator on the basis of X- andY-direction positions of the object so as to cancel, by said secondactuator, the reaction force to be received by said reaction forcecounter when the object is driven by said first actuator.
 2. Theapparatus according to claim 1, wherein said controller calculates X-and Y-direction accelerations of the object on the basis of the X- andY-direction positions of the object, and controls said second actuatoron the basis of the X- and Y-direction positions of the object and theX- and Y-direction accelerations of the object.
 3. The apparatusaccording to claim 1, further comprising an acceleration sensor whichdetects X- and Y-direction accelerations of the object from saidacceleration sensor, wherein said controller controls said secondactuator on the basis of the X- and Y-direction accelerations of theobject and the X- and Y-direction positions of the object.
 4. Theapparatus according to claim 1, wherein said controller controls saidsecond actuator so as to cancel, by said second actuator, X- andY-direction reaction forces and a moment reaction force which are to bereceived by said reaction force counter when the object is driven bysaid first actuator.
 5. The apparatus according to claim 1, wherein saidcontroller calculates X- and Y-direction reaction forces and a momentreaction force which are to be received by said reaction force counterwhen the object is driven by said first actuator, and generates aprofile to drive said reaction force counter on the basis of the X- andY-direction reaction forces and the moment reaction force.
 6. Theapparatus according to claim 5, wherein said controller calculates theX- and Y-direction reaction forces Fx and Fy to be received by saidreaction force counter and the moment reaction force Fr in accordancewith:Fx=m·AccXFy=m·AccY, andFr=y·Fx−x·Fy=m(y·AccX−x·AccY) where m, x, and y are a weight,X-direction position, and Y-direction position, respectively, of theobject, and AccX and AccY are X- and Y-direction accelerations,respectively.
 7. The apparatus according to claim 6, wherein saidcontroller generates a profile to drive said reaction force counter suchthat Σ(FMx)=−Fx, Σ(FMy)=−Fy, and Σ(FMr)=−Fr are established where Σ(FMx)and Z (FMy) are sums of X- and Y-direction thrusts, respectively, ofsaid second actuator, and Σ(FMr) is a sum of moment thrusts.
 8. Theapparatus according to claim 7, wherein the profile comprises a profilethat provides a thrust command value.
 9. The apparatus according toclaim 1, wherein said controller generates a profile to drive saidsecond actuator such that Σ(M(i) AccMX(i))=−Fx, Σ(M(i)·AccMY(i))=−Fy,and Σ(J(i)·AccMJ(i))=−Fr are established where (M(i) is a weight of eachof a plurality of reaction counters which receive the reaction forcegenerated when said first actuator drives the object, AccMX(i) andAccMY(i) are respectively X- and Y-direction accelerations of each ofsaid plurality of reaction force counters, and J(i) and AccMJ(i) arerespectively a moment of inertia and angular velocity of each of saidplurality of reaction force counters.
 10. The apparatus according toclaim 9, wherein the profile comprises a profile that provides anacceleration command value.
 11. The apparatus according to claim 10,wherein said controller converts the acceleration command value into aspeed command value and controls said second actuator with the speedcommand value.
 12. The apparatus according to claim 10, wherein saidcontroller converts the acceleration command value into a positioncommand value and controls said second actuator with the positioncommand value.
 13. The apparatus according to claim 1, wherein saidreaction force counter includes a stator of said first actuator.
 14. Theapparatus according to claim 1, wherein said controller controls saidsecond actuator to gradually decelerate said reaction force counter whena speed of said reaction force counter is not zero while a speed of theobject is zero.
 15. An exposure apparatus which has a chuck andtransfers or draws a pattern onto a substrate chucked on said chuck, andin which said chuck is driven by a driving apparatus according toclaim
 1. 16. A device manufacturing method of manufacturing a device byusing an exposure apparatus according to claim 15.